Did you ever get back to this? I think a properly refined kamm would be a really good fuel economy mod. We did figure out that the 2017 spoiler has been lifted up a bit to optimize aerodynamics. I wonder if we can shim up the 2014-2015 spoiler? I'd imagine your kamm would work much better then.

I want this mod. I remember in the day Porsche had a long tail for their 917 that reduced drag so much that close to 20mph was gained. Stability went out the window but I doubt we'll be driving 232mph on the Mulsanne straight.

Zero, my 2014 ES Plus gone but not forgotten. We're driving the Beetle of the 21st century